This invention relates to metallocene compositions and their use in the preparation of catalyst systems for olefin polymerization, particularly propylene polymerization.
The use of metallocene compositions in olefin polymerization is well known. Metallocenes containing substituted, bridged indenyl derivatives are noted for their ability to produce isotactic propylene polymers having high isotacticity and narrow molecular weight distribution. Considerable effort has been made toward obtaining metallocene produced propylene polymers having ever-higher molecular weight and melting point, while maintaining suitable catalyst activity.
Toward this end it has been found that there is a direct relationship between the way in which a metallocene is substituted, and the molecular structure of the resulting polymer. For the substituted, bridged indenyl type metallocenes, it is now well established that the type and arrangement of substituents on the indenyl groups, as well as the type of bridge connecting the indenyl groups, determines such polymer attributes as molecular weight and melting point. Unfortunately, it is impossible at this time to accurately correlate specific substitution or bridging patterns with specific polymer attributes, though trends may be identified.
For example, U.S. Pat. No. 5,840,644 describes certain metallocenes containing aryl-substituted indenyl derivatives as ligands, which are said to provide propylene polymers having high isotacticity, narrow molecular weight distribution and very high molecular weight.
Likewise, U.S. Pat. No. 5,936,053 describes certain metallocene compounds said to be useful for producing high molecular weight propylene polymers. These metallocenes have a specific hydrocarbon substituent at the 2 position and an unsubstituted aryl substituent at the 4 position, on each indenyl group of the metallocene compound.
WO 98/40419 and WO 99/42497 both describe certain supported catalyst systems for producing propylene polymers having high melting point. Metallocene compositions and their activators are often combined with a support material in order to obtain a catalyst system that is less likely to cause reactor fouling. However, it is known that supported metallocene catalyst systems tend to result in a polymer having lower melting point than would otherwise be obtained if the metallocene were not supported.
Much of the current research in this area has been directed toward using metallocene catalyst systems under commercially relevant process conditions, to obtain propylene polymers having melting points higher than known metallocene catalyst systems and close to, or as high as, propylene polymers obtained using conventional, Ziegler-Natta catalyst systems, i.e., 160xc2x0 C. or higher. The present inventors have discovered metallocene compounds that have this capability.
The present invention relates generally to metallocene compounds represented by the formula: 
wherein:
M is a metal of Group 4, 5, or 6 of the Periodic Table preferably, zirconium, hafnium and titanium, most preferably zirconium;
R1 and R2 are identical or different, preferably identical, and are one of a hydrogen atom, a C1-C10 alkyl group, preferably a C1-C3 alkyl group, a C1-C10 alkoxy group, preferably a C1-C3 alkoxy group, a C6-C10 aryl group, preferably a C6-C8 aryl group, a C6-C10 aryloxy group, preferably a C6-C8 aryloxy group, a C2-C10 alkenyl group, preferably a C2-C4 alkenyl group, a C7-C40 arylalkyl group, preferably a C7-C10 arylalkyl group, a C7-C40 alkylaryl group, preferably a C7-C12 alkylaryl group, a C8-C40 arylalkenyl group, preferably a C8-C12 arylalkenyl group, or a halogen atom, preferably chlorine; or a conjugated diene which is optionally substituted with one or more hydrocarbyl, tri(hydrocarbyl)silyl groups or hydrocarbyl, tri(hydrocarbyl)silylhydrocarbyl groups, said diene having up to 30 atoms not counting hydrogen;
R5 and R6 are identical or different, preferably identical, are one of a hydrogen atom, a halogen atom, preferably a fluorine, chlorine or bromine atom, a C1-C10 alkyl group, preferably a C1-C4 alkyl group, which may be halogenated, a C6-C10 aryl group, which may be halogenated, preferably a C6-C8 aryl group, a C2-C10 alkenyl group, preferably a C2-C4 alkenyl group, a C7-C40 arylalkyl group, preferably a C7-C10 arylalkyl group, a C7-C40 alkylaryl group, preferably a C7-C12 alkylaryl group, a C8-C40 arylalkenyl group, preferably a C8-C12 arylalkenyl group, a xe2x80x94NR215, xe2x80x94SR15, xe2x80x94OR15, xe2x80x94OSiR315 or xe2x80x94PR215 radical,
wherein:
R15 is one of a halogen atom, preferably a chlorine atom, a C1-C10 alkyl group, preferably a C1-C3 alkyl group, or a C6-C10 aryl group, preferably a C6-C9 aryl group;
R7 is 
wherein:
R17 to R24 are as defined for R1 and R2, or two or more adjacent radicals R17 to R24, including R20 and R21, together with the atoms connecting them form one or more rings;
M2 is carbon, silicon, germanium or tin;
the radicals R3, R4, and R10 are identical or different and have the meanings stated for R5 and R6, or two adjacent R10 radicals are joined together to form a ring, preferably a ring containing from about 4-6 carbon atoms.
More specifically, the present invention relates generally to metallocene compounds represented by the formula: 
wherein:
M1 is selected from the group consisting of titanium, zirconium, hafnium, vanadium niobium, tantalum, chromium, molybdenum and tungsten;
R1 and R2 are identical or different, and are one of a hydrogen atom, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C6-C10 aryl group, a C6-C10 aryloxy group, a C2-C10 alkenyl group, a C2-C40 alkenyl group, a C7-C40 arylalkyl group, a C7-C40 alkylaryl group, a C8-C40 arylalkenyl group, an OH group or a halogen atom; or a conjugated diene which is optionally substituted with one or more hydrocarbyl, tri(hydrocarbyl)silyl groups or hydrocarbyl, tri(hydrocarbyl)silylhydrocarbyl groups, said diene having up to 30 atoms not counting hydrogen;
R3 are identical or different and are each a hydrogen atom, a halogen atom, a C1-C10 alkyl group which may be halogenated, a C6-C10 aryl group which may be halogenated, a C2-C10 alkenyl group, a C7-C40-arylalkyl group, a C7-C40 alkylaryl group, a C8-C40 arylalkenyl group, a xe2x80x94NRxe2x80x22, xe2x80x94SRxe2x80x2, xe2x80x94ORxe2x80x2,xe2x80x94OSiRxe2x80x23 or xe2x80x94PRxe2x80x22 radical, wherein: Rxe2x80x2 is one of a halogen atom, a C1-C10 alkyl group, or a C6-C10 aryl group;
R4 to R7 are identical or different and are hydrogen, as defined for R3 or two or more adjacent radicals R5 to R7 together with the atoms connecting them form one or more rings;
R13 is represented by the formula: 
wherein:
R17 to R24 are as defined for R1 and R2, or two or more adjacent radicals R17 to R24, including R20 and R21, together with the atoms connecting them form one or more rings;
M2 is carbon, silicon, germanium or tin;
R8, R9, R10 R11 and R12 are identical or different and have the meanings stated for R4 to R7.
The present invention further relates to metallocene catalyst systems comprising one or more or the above compounds and one or more activators or cocatalysts, and optionally, support material, and to the use of such metallocene catalyst systems in olefin polymerization, particularly propylene polymer polymerization.
In one embodiment, the metallocenes of the present invention may be represented by the formula: 
wherein:
M is a metal of Group 4, 5, or 6 of the Periodic Table preferably, zirconium, hafnium and titanium, most preferably zirconium;
R1 and R2 are identical or different, preferably identical, and are one of a hydrogen atom, a C1-C10 alkyl group, preferably a C1-C3 alkyl group, a C1-C10 alkoxy group, preferably a C1-C3 alkoxy group, a C6-C10 aryl group, preferably a C6-C8 aryl group, a C6-C10 aryloxy group, preferably a C6-C8 aryloxy group, a C2-C10 alkenyl group, preferably a C2-C4 alkenyl group, a C7-C40 arylalkyl group, preferably a C7-C10 arylalkyl group, a C7-C40 alkylaryl group, preferably a C7-C12 alkylaryl group, a C8-C40 arylalkenyl group, preferably a C8-C12 arylalkenyl group, or a halogen atom, preferably chlorine; R1 and R2 may also be joined together to form an alkanediyl group or a conjugated C4-40 diene ligand which is coordinated to M1 in a metallocyclopentene fashion; R1 and R2 may also be identical or different conjugated dienes, optionally substituted with one or more hydrocarbyl, tri(hydrocarbyl)silyl groups or hydrocarbyl, tri(hydrocarbyl)silylhydrocarbyl groups, said dienes having up to 30 atoms not counting hydrogen and forming a xcfx80 complex with M, examples include, but are not limited to: 1,4-diphenyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3- pentadiene, 2,4-hexadiene, 1-phenyl-1,3-pentadiene, 1,4-dibenzyl-1,3-butadiene, 1,4-ditolyl-1,3-butadiene, 1,4-bis(trimethylsilyl)-1,3-butadiene, and 1,4-dinaphthyl-1,3-butadiene.
R5 and R6 are identical or different preferably identical, are one of a hydrogen atom, a halogen atom, preferably a fluorine, chlorine or bromine atom, a C1-C10 alkyl group, preferably a C1-C4 alkyl group, which may be halogenated, a C6-C10 aryl group, which may be halogenated, preferably a C6-C8 aryl group, a C2-C10 alkenyl group, preferably a C2-C4 alkenyl group, a C7-C40-arylalkyl group, preferably a C7-C10 arylalkyl group, a C7-C40 alkylaryl group, preferably a C7-C12 alkylaryl group, a C8-C40 arylalkenyl group, preferably a C8-C12 arylalkenyl group, a xe2x80x94NR215, xe2x80x94SR15, xe2x80x94OR15, xe2x80x94OSiR315 or xe2x80x94PR215 radical, wherein: R15 is one of a halogen atom, preferably a chlorine atom, a C1-C10 alkyl group, preferably a C1-C3 alkyl group, or a C6-C10 aryl group, preferably a C6-C9 aryl group;
R7is 
wherein:
R17 to R24 are as defined for R1 and R2, or two or more adjacent radicals R17 to R24, including R20 and R21, together with the atoms connecting them form one or more rings;
M2 is carbon, silicon, germanium or tin; and
the radicals R3, R4, and R10 are identical or different and have the meanings stated for R5 and R6, or two adjacent R10 radicals are joined together to form a ring, preferably a ring containing from about 4-6 carbon atoms.
Particularly preferred metallocenes of the present invention are represented by the formula: 
wherein:
M1 is selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten, preferably zirconium, hafnium or titanium, most preferably zirconium;
R1 and R2 are identical or different, and are one of a hydrogen atom, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C6-C10 aryl group, a C6-C10 aryloxy group, a C2-C10 alkenyl group, a C2-C40 alkenyl group, a C7-C40 arylalkyl group, a C7-C40 alkylaryl group, a C8-C40 arylalkenyl group, an OH group or a halogen atom, or are a conjugated diene which is optionally substituted with one or more hydrocarbyl, tri(hydrocarbyl)silyl groups or hydrocarbyl, tri(hydrocarbyl)silylhydrocarbyl groups, said diene having up to 30 atoms not counting hydrogen;
preferably R1 and R2 are identical and are a C1-C3 alkyl or alkoxy group, a C6-C8 aryl or aryloxy group, a C2-C4 alkenyl group, a C7-C10 arylalkyl group, a C7-C12 alkylaryl group, or a halogen atom, preferably chlorine;
R3 are identical or different and are each a hydrogen atom, a halogen atom, a C1-C10 alkyl group which may be halogenated, a C6-C10 aryl group which may be halogenated, a C2-C10 alkenyl group, a C7-C40-arylalkyl group, a C7-C40 alkylaryl group, a C8-C40 arylalkenyl group, a xe2x80x94NRxe2x80x22, xe2x80x94SRxe2x80x2, xe2x80x94ORxe2x80x2, xe2x80x94OSiRxe2x80x23 or xe2x80x94PRxe2x80x22 radical, wherein: Rxe2x80x2 is one of a halogen atom, a C1-C10 alkyl group, or a C6-C10 aryl group; preferably R3 is not a hydrogen atom;
preferably each R3 is identical and is a fluorine, chlorine or bromine, atom, a C1-C4 alkyl group which may be halogenated, a C6-C8 aryl group which may be halogenated, a xe2x80x94NRxe2x80x22, xe2x80x94SRxe2x80x2, xe2x80x94ORxe2x80x2, xe2x80x94OSiRxe2x80x23 or xe2x80x94PRxe2x80x22 radical, wherein: Rxe2x80x2 is one of a chlorine atom, a C1-C4 alkyl group, or a C6-C8 aryl group;
R4 to R7 are identical or different and are hydrogen, as defined for R3 or two or more adjacent radicals R5 to R7 together with the atoms connecting them form one or more rings;
R13 is represented by the formula: 
wherein:
R17 to R24 are as defined for R1 and R2, or two or more adjacent radicals R17 to R24, including R20 and R21, together with the atoms connecting them form one or more rings; preferably, R17 to R24 are hydrogen.
M2 is carbon, silicon, germanium or tin, preferably silicon; and
R8, R9, R10, R11 and R12 are identical or different and have the meanings stated for R4 to R7.
As utilized herein, the term xe2x80x9calkylxe2x80x9d, alone or in combination, means a straight-chain or branched-chain alkyl radical. Examples of such radicals include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl, hexyl, octyl and the like. The term xe2x80x9calkenylxe2x80x9d means a straight-chain or branched-chain hydrocarbon radial having one or more double bonds. Examples of suitable alkenyl radicals include, but are not limited to, ethenyl, propenyl, allyl, 1,4-butadienyl and the like. The term xe2x80x9calkoxyxe2x80x9d means an alkyl ether radical wherein: the term alkyl is as defined above. Examples of suitable alkyl ether radicals include, but are not limited to, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, sec-butoxy, tert-butoxy and the like. The term xe2x80x9carylxe2x80x9d means a phenyl, azulenyl, or naphthyl radical and the like which optionally contains a heteroatom and/or carries one or more substituents, for example, alkyl, alkoxy, halogen, hydroxy, amino, nitro etc.
The following are particularly preferred metallocenes:
rac-9-silafluorendiyl(2-methyl-4-phenylindenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-ethyl-4-phenylindenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-n-propyl-4-phenylindenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-iso-propyl-4-phenylindenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-n-butyl-4-phenylindenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-iso-butyl-4-phenylindenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-sec-butyl-4-phenylindenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-tert-butyl-4-phenylindenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-methyl-4-phenylindenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-ethyl-4-phenylindenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-n-propyl-4-phenylindenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-iso-propyl-4-phenylindenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-n-butyl-4-phenylindenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-iso-butyl-4-phenylindenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-sec-butyl-4-phenylindenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2tert-butyl-4-phenylindenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-methyl-4-phenylindenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-ethyl-4-phenylindenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-n-propyl-4-phenylindenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-iso-propyl-4-phenylindenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-n-butyl-4-phenylindenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-iso-butyl-4-phenylindenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-sec-butyl-4-phenylindenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-tert-butyl-4-phenylindenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-methyl4-phenylindenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-ethyl-4-phenylindenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-n-propyl-4-phenylindenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-iso-propyl4-phenylindenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-n-butyl-4-phenylindenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-iso-butyl-4-phenylindenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-sec-butyl-4-phenylindenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-tert-butyl-4-phenylindenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dichloride;
rac-dimethylsiladiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl) 2hafnium dichloride;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyI)2hafnium dichloride;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-bis- trifluoromethylphenyl]indenyl)2 hafnium dichloride;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-bis- trifluoromethylphenyl]indenyl)2 hafnium dichloride;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2, 5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2, 5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl2zirconium dichloride;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-iso-butyl 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl( 2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium dimethyl;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dichloride;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2hafnium dimethyl;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium dichloride;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-tbutylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-dimethylsiladiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-bis-trifluoromethylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2zirconium xcex74-1,4diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-iso-propylphenyl]indenyl)2hafnium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-methyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-ethyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-n-propyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-iso-propyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene,
rac-9-silafluorendiyl(2-n-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-iso-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene;
rac-9-silafluorendiyl(2-tert-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene; and
rac-9-silafluorendiyl(2-sec-butyl, 4-[3xe2x80x2,5xe2x80x2-di-phenylphenyl]indenyl)2zirconium xcex74-1,4-diphenyl-1,3-butadiene.
xe2x80x9c9-silafluorendiyl-xe2x80x9d refers to the substituent: 
The metallocenes of this invention are prepared according to general techniques known from the literature, for example U.S. Pat. Nos. 5,789,634 and 5,840,644 (both entirely incorporated herein by reference).
Generally, metallocenes of this type are synthesized as shown below. where (R4=H) (a) is an aryl-coupling reaction between a 4-halosubstituted indene and an aryl Grignard catalyzed by NiCl2(PPh3)2 in ether-type solvents at room temperature to reflux. Product is usually purified by column chromatography or distillation. (b) is a deprotonation via a metal salt of an alkyl anion (e.g. n-BuLi) to form an indenide followed by reaction with an appropriate bridging precursor as specified in the examples. Reactions are usually done in ether-type solvents at ambient temperatures. The final product is purified by column chromatography or distillation. (c) is double deprotonation via an alkyl anion (e.g. n-BuLi) to form a dianion followed by reaction with a metal halide (e.g. ZrCl4). The reaction are usually done in ether-type or aromatic solvents at ambient temperatures. The final products are obtained by recrystallization of the crude solids. 
The metallocenes of this invention are highly active catalyst components for the polymerization of olefins. The metallocenes are preferably employed as chiral racemates. However, it is also possible to use the pure enantiomers in the (+) or (xe2x88x92) form. The pure enantiomers allow an optically active polymer to be prepared. However, the meso form of the metallocenes should be removed, since the polymerization-active center (the metal atom) in these compounds is no longer chiral due to the mirror symmetry at the central metal atom and it is therefore not possible to produce a highly isotactic polymer. If the meso form is not removed, atactic polymer is formed in addition to isotactic polymer. For certain applications this may be entirely desirable.
Rac/meso metallocene isomer separation is facilitated when metallocenes containing certain bridging groups are prepared. We have found this to be true when the bridging group, R13, is represented by the formula: 
wherein:
M2 and R17 to R24 are as defined above.
Metallocenes are generally used in combination with some form of activator in order to create an active catalyst system. The terms xe2x80x9cactivatorxe2x80x9d and xe2x80x9ccocatalystxe2x80x9d are used interchangeably and are defined herein to mean any compound or component or combination of compounds or components, capable of enhancing the ability of one or more metallocenes to polymerize olefins. Alklyalumoxanes such as methylalumoxane (MAO) are commonly used as metallocene activators. Generally alkylalumoxanes contain 5 to 40 of the repeating units:
R(AlRO)xAlR2 for linear species and
(AlRO)x for cyclic species
where R is a C1-C8 alkyl including mixed alkyls. Compounds in which R is methyl are particularly preferred. Alumoxane solutions, particularly methylalumoxane solutions, may be obtained from commercial vendors as solutions having various concentrations. There are a variety of methods for preparing alumoxane, non-limiting examples of which are described in U.S. Pat. Nos. 4,665,208, 4,952,540, 5,091,352, 5,206,199, 5,204,419, 4,874,734, 4,924,018, 4,908,463, 4,968,827, 5,308,815, 5,329,032, 5,248,801, 5,235,081, 5,103,031 and EP-A-0 561 476, EP-B1-0 279 586, EP-A-0 594-218 and WO 94/10180, each fully incorporated herein by reference.
Ionizing activators may also be used to activate metallocenes. These activators are neutral or ionic, or are compounds such as tri(n-butyl)ammonium tetrakis(pentaflurophenyl)borate, which ionize the neutral metallocene compound. Such ionizing compounds may contain an active proton, or some other cation associated with, but not coordinated or only loosely coordinated to, the remaining ion of the ionizing compound. Combinations of activators may also be used, for example, alumoxane and ionizing activator combination, see for example, WO 94/07928.
Descriptions of ionic catalysts for coordination polymerization comprised of metallocene cations activated by non-coordinating anions appear in the early work in EP-A-0 277 003, EP-A-0 277 004 and U.S. Pat. No. 5,198,401 and WO-A-92/00333 (each incorporated herein by reference). These teach desirable methods of preparation wherein: metallocenes are protonated by an anion precursor such that an alkyl/hydride group is abstracted from a transition metal to make it both cationic and charge-balanced by the non-coordinating anion. Suitable ionic salts include tetrakis-substituted borate or aluminum salts having fluorided aryl-constituents such as phenyl, biphenyl and napthyl.
The term xe2x80x9cnon-coordinating anionxe2x80x9d (NCA) means an anion which either does not coordinate to said cation or which is only weakly coordinated to said cation thereby remaining sufficiently labile to be displaced by a neutral Lewis base. xe2x80x9cCompatiblexe2x80x9d non-coordinating anions are those which are not degraded to neutrality when the initially formed complex decomposes. Further, the anion will not transfer an anionic substituent or fragment to the cation so as to cause it to form a neutral four coordinate metallocene compound and a neutral by-product from the anion. Non-coordinating anions useful in accordance with this invention are those which are compatible, stabilize the metallocene cation in the sense of balancing its ionic charge at +1, yet retain sufficient lability to permit displacement by an ethylenically or acetylenically unsaturated monomer during polymerization.
The use of ionizing ionic compounds not containing an active proton but capable of producing both the active metallocene cation and a non-coordinating anion is also known. See, for example, EP-A-0 426 637 and EP-A-0 573 403 (each incorporated herein by reference). An additional method of making the ionic catalysts uses ionizing anion precursors which are initially neutral Lewis acids but form the cation and anion upon ionizing reaction with the metallocene compounds, for example the use of tris(pentafluorophenyl) borane. See EP-A-0 520 732 (incorporated herein by reference). Ionic catalysts for addition polymerization can also be prepared by oxidation of the metal centers of transition metal compounds by anion precursors containing metallic oxidizing groups along with the anion groups, see EP-A-0 495 375 (incorporated herein by reference).
Where the metal ligands include halogen moieties (for example, bis-cyclopentadienyl zirconium dichloride) which are not capable of ionizing abstraction under standard conditions, they can be converted via known alkylation reactions with organometallic compounds such as lithium or aluminum hydrides or alkyls, alkylalumoxanes, Grignard reagents, etc. See EP-A-0 500 944 and EP-A1-0 570 982 (each incorporated herein by reference) for in situ processes describing the reaction of alkyl aluminum compounds with dihalo-substituted metallocene compounds prior to or with the addition of activating anionic compounds.
Methods for supporting ionic catalysts comprising metallocene cations and NCA are described in WO 9950311, U.S. Pat. Nos. 5,643,847 and 5,972,823, U.S. patent application Ser. No. 09184358, filed Nov. 2, 1998 and U.S. patent application Ser. No. 09184389, filed Nov. 2, 1998 (each fully incorporated herein by reference).
When the activator for the metallocene supported catalyst composition is a NCA, preferably the NCA is first added to the support composition followed by the addition of the metallocene catalyst. When the activator is MAO, preferably the MAO and metallocene catalyst are dissolved together in solution. The support is then contacted with the MAO/metallocene catalyst solution. Other methods and order of addition will be apparent to those skilled in the art.
The catalyst systems used to prepare the compositions of this invention are preferably supported using a porous particulate material, such as for example, talc, inorganic oxides, inorganic chlorides such as magnesium chloride, and resinous materials such as polyolefin or polymeric compounds.
Preferably, the support materials are porous inorganic oxide materials, which include those from the Periodic Table of Elements of Groups 2, 3, 4, 5, 13 or 14 metal/metalloid oxides. Silica, alumina, silica-alumina, and mixtures thereof are particularly preferable. Other inorganic oxides that may be employed either alone or in combination with the silica, alumina or silica-alumina are magnesia, titania, zirconia, and the like.
Preferably the support material is porous silica which has a surface area in the range of from 10 to 700 m2/g, a total pore volume in the range of from 0.1 to 4.0 cc/g and an average particle size in the range of from 10 to 500 xcexcm. More preferably, the surface area is in the range of from 50 to 500 m2/g, the pore volume is in the range of from 0.5 to 3.5 cc/g and the average particle size is in the range of from 20 to 200 xcexcm. Most desirably the surface area is in the range of from 100 to 400 m2/g, the pore volume is in the range of from 0.8 to 3.0 cc/g and the average particle size is in the range of from 30 to 100 xcexcm. The average pore size of typical porous support materials is in the range of from 10 to 1000 xc3x85. Preferably, a support material is used that has an average pore diameter of from 50 to 500 xc3x85, and most desirably from 75 to 350 xc3x85. It may be particularly desirable to dehydrate the silica at a temperature of from 100xc2x0 C. to 800xc2x0 C. anywhere from 3 to 24 hours.
The metallocene, activator and support material may be combined in any number of ways. More than one metallocene may also be used. Examples of suitable support techniques are described in U.S. Pat. Nos. 4,808,561 and 4,701,432 (each fully incorporated herein by reference.). Preferably the metallocenes and activator are combined and their reaction product supported on the porous support material as described in U.S. Pat. No. 5,240,894 and WO 94/28034, WO 96/00243, and WO 96/00245 (each fully incorporated herein by reference.) Alternatively, the metallocenes may be preactivated separately and then combined with the support material either separately or together. If the metallocenes are separately supported, then preferably, they are dried then combined as a powder before use in polymerization.
Regardless of whether the metallocene(s) and their activator are separately precontacted or whether the metallocene(s) and activator are combined at once, in some instances it may be preferred that the total volume of reaction solution applied to porous support is less than 4 times the total pore volume of the porous support, more preferably less than 3 times the total pore volume of the porous support and even more preferably in the range of from more than 1 to less than 2.5 times the total pore volume of the porous support. Procedures for measuring the total pore volume of porous support are well known in the art. One such method is described in Volume 1, Experimental Methods in Catalyst Research, Academic Press, 1968, pages 67-96.
The supported catalyst system may be used directly in polymerization or the catalyst system may be prepolymerized using methods well known in the art. For details regarding prepolymerization, see U.S. Pat. Nos. 4,923,833 and 4,921,825, and EP 0 279 863 and EP 0 354 893 (each fully incorporated herein by reference).
The metallocene catalyst systems described herein are useful in the polymerization of all types of olefins. This includes polymerization processes which produce homopolymers, copolymers, terpolymers and the like as well as block copolymers and impact copolymers. These polymerization processes may be carried out in solution, in suspension or in the gas phase, continuously or batchwise, or any combination thereof, in one or more steps, preferably at a temperature of from 60xc2x0 C. to 200xc2x0 C., more preferably from 30xc2x0 C. to 80xc2x0 C., particularly preferably from 50xc2x0 C. to 80xc2x0 C. The polymerization or copolymerization is carried out using olefins of the formula RaCHxe2x95x90CHxe2x80x94Rb. In this formula, Ra and Rb are identical or different and are a hydrogen atom or an alkyl radical having 1 to 14 carbon atoms. However, Ra and Rb may alternatively form a ring together with the carbon atoms connecting them. Examples of such olefins are ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, norbornene and norbornadiene. In particular, propylene and ethylene are polymerized. The metallocenes and metallocenes catalyst systems of this invention are most suitable for the polymerization of propylene based polymers.
If necessary, hydrogen is added as a molecular-weight regulator and/or in order to increase the activity. The overall pressure polymerization system is from 0.5 to 100 bar. Polymerization is preferably carried out in the industrially particularly interesting pressure range from 5 to 64 bar.
Typically, the metallocene is used in the polymerization in a concentration, based on the transition metal, of from 10xe2x88x923 to 10xe2x88x928 mol, preferably from 10xe2x88x924 to 10xe2x88x927 mol, of transition metal per dm3 of solvent or per dm3 of reactor volume. When alumoxane is used as the cocatalyst, it is used in a concentration of from 10xe2x88x925 to 10xe2x88x921 mol, preferably from 10xe2x88x924 to 10xe2x88x922 mol, per dm3 of solvent or per dm3 of reactor volume. The other cocatalysts mentioned are used in an approximately equimolar amount with respect to the metallocene. In principle, however, higher concentrations are also possible.
If the polymerization is carried out as a suspension or solution polymerization, an inert solvent which is customary for the Ziegler low-pressure process is typically used for example, the polymerization is carried out in an aliphatic or cycloaliphatic hydrocarbon; examples of which are propane, butane, hexane, heptane, isooctane, cyclohexane and methylcyclohexane. It is also possible to use a benzene or hydrogenated diesel oil fraction. Toluene can also be used. The polymerization is preferably carried out in the liquid monomer. If inert solvents are used, the monomers are metered in gas or liquid form.
Before addition of the catalyst, in particular of the supported catalyst system, another alkylaluminum compound, such as, for example, trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum or isoprenylaluminum, may additionally be introduced into the reactor in order to render the polymerization system inert (for example to remove catalyst poisons present in the olefin). This compound is added to the polymerization system in a concentration of from 100 to 0.01 mmol of Al per kg of reactor contents. Preference is given to triisobutylaluminum and triethylaluminum in a concentration of from 10 to 0.1 mmol of Al per kg of reactor contents. This allows the molar Al/M1 ratio to be selected at a low level in the synthesis of a supported catalyst system.
In principle, however, the use of further substances for catalysis of the polymerization reaction is unnecessary, i.e. the systems according to the invention can be used as the only catalysts for the polymerization of olefins.
The process according to the invention is distinguished by the fact that the metallocenes described can give propylene polymers of very high molecular weight, melting point, and very high stereotacticity, with high catalyst activities in the industrially particularly interesting polymerization temperature range of from 50xc2x0 C. to 80xc2x0 C.
The catalyst systems of this invention are capable of providing polymers, particularly propylene homopolymers and copolymers, of exceptionally high molecular weight and melting point even when used in processes under commercially relevant conditions of temperature, pressure and catalyst activity. Preferred melting points are at least as high as 155xc2x0 C., more preferably at least 157xc2x0 C., even more preferably at least 157xc2x0 C., and most preferably 160xc2x0 C. or more.
The catalyst systems of this invention are also capable of providing propylene polymers having high stereospecificity and regiospecificity. Isotactic propylene polymers prepared according to the processes of this invention may have a proportion of 2-1-inserted propene units of less than 0.5%, at a triad tacticity of greater than 98%. Preferably there is no measurable proportion of 2-1-inserted propene units. Triad tacticity is determined using 13C-NMR according to J. C. Randall, Polymer Sequence Determination: Carbon-13 NMR Method, Academic Press New York 1978. Polymers prepared using the processes of described herein find uses in all applications including fibers, injection-molded parts, films, pipes etc.
While the present invention has been described and illustrated by reference to particular embodiments, it will be appreciated by those of ordinary skill in the art, that the invention lends itself to many different variations not illustrated herein. For these reasons, then, reference should be made solely to the appended claims for purposes of determining the true scope of the present invention.
Although the appendant claims have single appendencies in accordance with U.S. patent practice, each of the features in any of the appendant claims can be combined with each of the features of other appendant claims or the main claim.